Number System If A + B = 30 and AB = 94, What is the value of A² + B² ? 625 824 712 920 625 824 712 920 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP (A + B)² = (30)² = 900A² + B² + 2AB = 900Therefore, A² + B² = 900 - 2 x 94 = 900 - 188 = 712
Number System The average of 7 numbers is 15, that of the first three is 6 and that of the last three is 23. What is the fourth number? 7 15 13 18 7 15 13 18 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP 4th No. = (Total of 7 Nos) - (Total of first three + total of last 3) = (15 x 7) - (6 x 3 + 23 x 3) = 105 - (18 + 69) =105 - 87 = 18
Number System Sum of two consecutive even terms lacks by 98 from their product. Find the sum of these number 18 None 24 32 18 None 24 32 ANSWER DOWNLOAD EXAMIANS APP
Number System If the difference between the squares of two consecutive numbers is 47, what is the smaller number ? 23 25 24 26 23 25 24 26 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Let the numbers be (x + 1) and x.Therefore, (x + 1)² - x² = 47x² + 2x + 1 - x² = 472x + 1 = 47Therefore, x = 46/2 = 23
Number System The sum of the ages of a son and father is 65 years. After 5 years the age of father will be double of the age of son. What is the age of son ? 19 years 20 years 18 years 17 years 19 years 20 years 18 years 17 years ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Let the age of the son be x and the age of the father be y.Therefore, x + y = 65 ..........(i)or, 2 x (x + 5) = (y + 5)or, 2x + 10 = y + 5or, 2x - y = 5 ...................(ii)From equations (i) and (ii), x = 20, y = 45
Number System What is the least number that should be added to 5200 to make it a perfect square ? 129 288 225 275 129 288 225 275 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP We sec (73)² = 5329 and (72)² = 5184ie 5329 > 5200 > 5184So 129 should be added to make is perfect square.
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